Inflator

ABSTRACT

An inflator ( 22 ) for providing inflation fluid ( ) to inflate an inflatable vehicle occupant protection device ( 14 ) includes a container ( 30 ) storing the inflation fluid under pressure. The container ( 30 ) has an outlet passage ( 80 ) through which the inflation fluid flows from the container. A rupturable closure member ( 92 ) fixed to the container ( 30 ) blocks flow of inflation fluid through the passage ( 80 ). A support ( 100 ) for the rupturable closure member ( 92 ) defines a chamber ( 110 ) adjacent the rupturable closure member ( 92 ). The rupturable closure member ( 92 ) has a first portion ( 122 ) deformed into the chamber ( 110 ) by the pressure of the inflation fluid and a second ring-shaped portion ( 124 ) encircling the first portion ( 122 ). An initiator ( 98 ) ruptures the closure member ( 92 ) when actuated by shearing the first portion ( 122 ) from the second portion ( 124 ).

RELATED APPLICATION

[0001] This application is a divisional of U.S. patent application Ser.No. 09/371,776, filed Aug. 10, 1999.

FIELD OF THE INVENTION

[0002] The present invention relates to an inflator which providesinflation fluid to inflate an inflatable vehicle occupant protectiondevice and, more specifically, to an inflator in which a rupturableclosure member is supported.

BACKGROUND OF THE INVENTION

[0003] An inflatable vehicle occupant protection device, such as a sidecurtain or an air bag, is inflated upon the occurrence of a vehiclecondition requiring inflation of the side curtain or air bag. Wheninflation is required, an inflator is actuated to provide inflationfluid which inflates the side curtain or air bag into the vehicleoccupant compartment.

[0004] The inflator includes a container defining an inflation fluidpressure chamber with an outlet passage. A rupturable closure member isfixed to the container to block flow of inflation fluid through theoutlet passage. The inflator further includes an electrically actuatableinitiator which, when actuated, causes the closure member to rupture sothat inflation fluid in the pressure chamber can flow from the inflator.

SUMMARY OF THE INVENTION

[0005] The present invention is an inflator for providing inflationfluid to inflate an inflatable vehicle occupant protection device. Theinflator includes a container storing inflation fluid under pressure.The container has an outlet passage through which inflation fluid flowsfrom the container. A rupturable closure member fixed to the containerblocks flow of inflation fluid through the outlet passage.

[0006] A support for the rupturable closure member defines a chamberadjacent the rupturable closure member. The rupturable closure memberhas a first portion deformed into the chamber by the pressure of theinflation fluid and a second ring-shaped portion encircling the firstportion. An initiator ruptures the closure member by shearing the firstportion from the second portion when actuated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The foregoing and other features of the present invention willbecome apparent to one skilled in the art to which the present inventionrelates upon consideration of the following description of the inventionwith reference to the accompanying drawings, wherein:

[0008]FIG. 1 is a schematic illustration of a vehicle safety apparatusembodying the present invention;

[0009]FIG. 2 is an enlarged sectional view of an inflator of the safetyapparatus of FIG. 1;

[0010]FIG. 3 is an enlarged view of a portion of the is inflator of FIG.2;

[0011]FIG. 4 is a view similar to FIG. 3 showing a rupturable closuremember prior to inflation fluid entering a container which is closed bythe closure member;

[0012]FIG. 5 is a view similar to FIG. 3 showing the closure memberafter an initiator of the inflator has been actuated;

[0013]FIG. 6 is a view similar to FIG. 5 showing a portion of theclosure member sheared away; and

[0014]FIG. 7 is a view similar to FIG. 6 showing the closure memberduring flow of inflation fluid from the container.

DESCRIPTION OF A PREFERRED EMBODIMENT

[0015] The present invention relates to a vehicle occupant safetyapparatus. In particular, the present invention relates to an inflatablevehicle occupant protection device, such as a side curtain assembly, forhelping to protect a vehicle occupant in the event of a side impact to avehicle. As representative of the present invention, FIG. 1 illustratesschematically a vehicle safety apparatus 10 for helping to protect anoccupant of a vehicle 12.

[0016] The safety apparatus 10 includes an inflatable vehicle occupantprotection device in the form of a side curtain 14. The side curtain 14is mounted adjacent the side structure 16 of the vehicle 12. A fill tube20 extends into the side curtain 14. An actuatable inflator 22, whenactuated, directs fluid into the fill tube 20 which, in turn, directsfluid into the inflatable side curtain 14 to inflate the side curtain.The side curtain 14 is inflated from a deflated and stowed condition(not shown) to an inflated condition, as illustrated in FIG. 1. In itsinflated condition, the side curtain 14 is positioned between the sidestructure of the vehicle and a vehicle occupant. The side curtain 14 ismade of a material having a low permeability so that the side curtainremains inflated for a long period of time, such as seven seconds orlonger.

[0017] The vehicle 12 includes a sensor 24, known in the art, forsensing a side impact to the vehicle and/or a vehicle rollover, toactuate the inflator 22. The sensor 24 may include vehicle electriccircuitry for actuating the inflator 22 in response to sensing a sideimpact to the vehicle and/or a vehicle rollover. The sensor 24 providesan electric signal over lead wires 26 to the inflator 22, when theinflator is to be actuated.

[0018] The inflator 22 (FIG. 2) comprises a source of inflation fluidfor the side curtain 14. The inflator 22 includes a container 30 havinga generally elongate configuration including a main body portion 32 andan end cap 34. The end cap 34 is affixed to an open end 33 of the mainbody portion 32 by friction welding. The end cap 34 could, however, beconnected to the main body portion 32 in any manner known in the art,such as using laser welds, brazing or screw threads.

[0019] The main body portion 32 of the container 30 has a tubular,cylindrical configuration including an axially extending cylindricalside wall 40. The side wall 40 has a cylindrical inner surface 42centered on a longitudinal central axis 44 of the inflator 22. A secondend portion 46 of the main body portion 32 is closed by a domed end wall48. The side wall 40 and the end wall 48 define a chamber 50 in thecontainer 30.

[0020] The chamber 50 contains pressurized inflation fluid. Theinflation fluid stored in the chamber 50 preferably consists essentiallyof helium at a storage pressure within the range of about 4,000 psi toabout 7,000 psi. The inflation fluid may, however, have any othercomposition and storage pressure suitable for inflating the side curtain14.

[0021] The end cap 34 (FIGS. 2 and 3) of the container 30 has agenerally cylindrical configuration including an axially extendingcylindrical side wall 70 and an end surface 72. An annular array ofinflation fluid outlet passages 76 are formed in the side wall 70 of theend cap 34. The flow area, number and/or configuration of the outletpassages 76 may be selected to restrict or otherwise control the flow ofinflation fluid into the side curtain 14 through the fill tube 20, whichis connected in a known manner to the end cap 34, as illustratedschematically in FIG. 1.

[0022] The end cap 34 includes a surface 78 (FIG. 2) which extendsgenerally parallel to the end surface 72. A passage 80 extends axiallythrough the end cap 34 and intersects the surface 78. The passage 80conducts inflation fluid from the chamber 50 to the outlet passages 76.The passage 80 is centered on the axis 44.

[0023] A rupturable closure member 92 (FIGS. 2 and 3), such as a rupturedisk, is affixed to the surface 78 by a laser weld 94. The rupture disk92 could, however, be connected to the surface 78 in any manner wellknown in the art, such as by brazing, projection welding or electronbeam welding. The rupture disk 92 is centered on the axis 44 and blocksthe flow of inflation fluid through the passage 80 and to the passages76.

[0024] An initiator 98 centered on the axis 44 is housed in a hollowsupport 100 which supports the closure member 92. Lead wires 26 extendfrom connector pins 101 of the initiator 98 to receive the electricalsignal from the sensor 24. The support 100 is centered on the axis 44.The support 100 (FIGS. 2 and 3) has a flange 102 which engages the endsurface 72 of the end cap 34. The flange 102 extends radially outward ofthe support 100 and also engages a radially extending base 104 of theinitiator 98.

[0025] An annular rim portion 106 extends from the end surface 72. Therim portion 106 initially projects axially away from the end surface 72and is subsequently crimped around the base 104 of the initiator 98 tohold the initiator and the support 100 in place in the end cap 34.Alternatively, the initiator 98 and the support 100 may be welded to theend cap 34 to retain the initiator and the support in the end cap.

[0026] The support 100 projects inwardly along the axis 44 into abutmentwith the closure member 92. The support 100 is thus mounted in a loadbearing relationship with the closure member 92. More specifically, theclosure member 92 is subjected to the storage pressure of the inflationfluid in the chamber 50. Therefore, the closure member 92 transmits afluid storage pressure force axially outward against the support 100.The support 100, in turn, transmits the storage pressure force to theend surface 72 of the end cap 34 where the initiator 98 adjoins thecrimped rim 106 of the end surface 72.

[0027] The support 100 defines a chamber 110. An end portion 112 of thesupport 100 has a circular rim 114 engaging the closure member 92. Therim 114 defines an opening 116 into the chamber 110.

[0028] The closure member 92 has a central dome-shaped portion 122extending into the chamber 110. A portion 124 of the closure member 92encircles the dome-shaped portion 122. The portion 124 of the closuremember 92 extends from the circular rim 114 of the support 100 to thesurface 78 of the end cap 34. A portion 126 of the closure member 92encircles the portion 124 and is welded to the surface 78.

[0029] When the chamber 50 is not filled with inflation fluid, as shownin FIG. 4, the closure member 92 is a flat disk. The closure member 92is spaced from the rim 114 of the support 100. During the subsequentloading of the closure member 92 by the pressure of the inflation fluid,the closure member is stressed and undergoes plastic deformation intothe chamber 110. The closure member 92 deforms from the flat disk shownin FIG. 4 into the shape shown in FIG. 3. A work hardening of theclosure member 92 occurs during the plastic deformation.

[0030] Upon receiving of an electric signal from the sensor 24, theinitiator 98 is actuated in a known manner to produce a shock wave andcombustion gas. The pressure of the combustion gas, coupled with theshock wave, acts on the dome-shaped portion 122 of the closure member 92to reverse the dome from the position shown in FIG. 3 to the positionshown in FIG. 5.

[0031] The large movement of the dome 122 shears the dome out of theclosure member 92, as shown in FIG. 6. The portion 124 of the closuremember 92 continues to block the passage 80. The pressure generated bythe inflation fluid is supported only by the strength of the portion 124when the dome 122 is removed. The pressure of the inflation fluid causesthe portion 124 of the closure member 92 to rip and petal away from thesupport 100 to the position shown in FIG. 7, providing a flow of theinflation fluid through the passage 80 and to the outlet passages 76 andthereafter to the side curtain 14.

[0032] From the above description of the invention, those skilled in theart will perceive improvements, changes and modifications. For example,although the inflator 22 is shown being used with a side curtain 14, theinflator could be used in any known inflatable vehicle occupantprotection device such as air bags, inflatable seat belts, inflatableknee bolsters, inflatable air bags to operate knee bolsters, andinflatable head liners. Such improvements, changes and modificationswithin the skill of the art are intended to be covered by the appendedclaims.

Having described the invention, the following is claimed:
 1. A systemfor helping to protect an occupant of a vehicle including a sidestructure, said system comprising: an inflatable vehicle occupantprotection device inflatable to an inflated condition for helping toprotect an occupant of the vehicle, said inflatable vehicle occupantprotection device when in said inflated condition being positionedbetween the side structure of the vehicle and a vehicle occupant; anapparatus for providing inflation fluid for inflating said inflatablevehicle occupant protection device, said apparatus comprising acontainer containing a volume of stored inflation fluid under pressure,said volume of stored inflation fluid being sufficient to inflate saidinflatable vehicle occupant protection device to said inflated conditionand maintain said inflatable vehicle occupant protection device in saidinflated condition for at least seven seconds; and an initiator foractuating said apparatus to cause said apparatus to release said volumeof stored inflation fluid into said inflatable vehicle occupantprotection device to inflate said inflatable vehicle occupant protectiondevice to said inflated condition and maintain said inflatable vehicleoccupant protection device in said inflated condition for at least sevenseconds.
 2. The system recited in claim 1, further comprising a filltube having a portion located in said inflatable vehicle occupantprotection device, said fill tube delivering said inflation fluid tosaid inflatable vehicle occupant protection device to inflate saidinflatable vehicle occupant protection device.
 3. The system recited inclaim 1, wherein said container includes an outlet passage through whichsaid inflation fluid flows from said container toward said inflatablevehicle occupant protection device, said apparatus further comprising arupturable closure member fixed to said container and blocking flow ofsaid inflation fluid through said passage, said initiator which, whenactuated, causing said closure member to rupture to allow said inflationfluid to flow through said passage.
 4. The system as recited in claim 3,further comprising a support for supporting said closure member againstthe pressure of said inflation fluid in said container, said initiator,when actuated, causing said closure member to rupture under the pressureof said inflation fluid and opening said passage to provide a flow ofinflation fluid from said container through said passage.
 5. Apparatusfor helping to protect an occupant of a vehicle including a sidestructure, said apparatus comprising: an inflatable vehicle occupantprotection device inflatable to an inflated condition for helping toprotect an occupant of the vehicle, said inflatable vehicle occupantprotection device when in said inflated condition being positionedbetween the side structure of the vehicle and a vehicle occupant; acontainer containing a volume of stored inflation fluid under pressure,said volume of stored inflation fluid being sufficient to inflate saidinflatable vehicle occupant protection device to said inflated conditionand maintain said inflatable vehicle occupant protection device in saidinflated condition for at least seven seconds; a rupturable closuremember fixed to said container and blocking flow of inflation fluid fromsaid container; and an initiator actuatable to rupture said closuremember to release said inflation fluid from said container into saidinflatable vehicle occupant protection device to inflate said inflatablevehicle occupant protection device to said inflated condition andmaintain said inflatable vehicle occupant protection device in saidinflated condition for at least seven seconds.